

body {
  padding: 0;
  margin: 0;
  align-items: center;
  justify-content: center;
  height: 100vh;
}

h1 {
  font-size: 5em;
  text-align: center;
  font-weight: 200;
  color: #fff;
  opacity: 1;
  text-shadow: 1px 1px 2px rgba(255,255,255,1);
}

.canvas {
  background-position: top center;
	background-attachment:fixed;
  background-repeat: no-repeat;
  -webkit-background-size: cover;/*把背景图像扩展至足够大*/
	-o-background-size: cover;
	-moz-background-size: cover;
	background-size: cover;
  position: fixed;
  	/*方式1*/
  	/*z-index:-1;*/
  top: 0;
  left: 0;
  pointer-events: none;
}
